6 Movie Characters Who Knew Too Much

Szell has a good reason for asking him this – Levy's secret agent brother walked a long way through New York with a knife wound in his stomach to make it to his apartment. Does Levy really expect Szell to believe that he stumbled all the way there just to die on the floor without telling him anything? Here's the joke: That's exactly what happened. Sometimes you can know too much without knowing much of anything at all.

Joe Frady, "The Parallax View"

Caul, "The Conversation"

Harry Caul is a surveillance expert – one of the best in the field. But he's got this weird hang-up about his surveillance data being used to facilitate murder. So when a seemingly innocent conversation he's hired to record begins to tweak his suspicions, he goes to lengths to protect the people involved. But just because you know too much doesn't mean you understand anything – and that's a lesson that Harry Caul learns the moderate-to-severe way.

Nora Davis, "The Girl Who Knew Too Much"

Often considered the first "giallo" thriller in movie history, "The Girl Who Knew Too Much" utilizes the common plot giallo plot point of a character who learns too much about a serial killer on the loose – and who thus becomes a target of the murderer. In Davis' case, she is dismissed by many as a "hysterical female," so she ends up having to entrap the killer herself.

Marcus Daly, "Deep Red"

giallo we come to one of the best – Dario Argento's "Deep Red." Like Nora, Marcus (played by David Hemmings, familiar to the sensation of knowing too much after "Blow-Up") accidentally sees a clue to a brutal murder. But, as is often the case in Argento's films, that clue is locked away in his psyche, and he can only dig it out with a lot of exhaustive research and investigating (the targets of which often end up murdered themselves).